Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and a rotor. The rotor typically includes a rotatable hub having one or more rotor blades attached thereto. A pitch bearing is typically configured operably between the hub and the rotor blade to allow for rotation about a pitch axis. The rotor blades capture kinetic energy of wind using known airfoil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
A power output of the generator increases with wind speed until the wind speed reaches a rated wind speed for the turbine. At and above the rated wind speed, the generator operates at a rated power. The rated power is an output power at which the generator can operate with a level of fatigue or extreme load to turbine components that is predetermined to be acceptable. At wind speeds higher than a certain speed, typically referred to as a “trip limit” or “monitor set point limit,” the wind turbine may implement a control action, such as shutting down or de-rating the wind turbine in order to protect wind turbine components from damage.
At times, wind turbines may experience sudden change in wind speed or wind direction or sudden changes in wind speed and wind direction simultaneously due to stochastic nature of wind. Sudden changes in wind speed or wind direction causes extreme loading on the wind turbine. In order to minimize the impact of extreme loads on the wind turbine, conventional protection control schemes shut down the wind turbine when the change in the wind direction exceeds predetermined threshold limits.
Conventional protection control schemes can lead to a large number of trips in the field, which impacts the availability of the wind turbine to produce power. Such control schemes can also cause higher than normal operation extreme loading on various wind turbine components.
Accordingly, systems and methods for protecting wind turbines during extreme wind gusts or for early detection of extreme wind gusts so as to reduce the shut down time and/or reduce the number of trips associated with conventional control schemes would be desired in the art.